A Review of Zinc-L-Carnosine and Its Positive Effects on Oral Mucositis, Taste Disorders, and Gastrointestinal Disorders

A comprehensive review on physiological and biological activities of carnosine: turning from preclinical facts to potential clinical applications

Carnosine, a compound with plethora of benefits, was originally discovered in 1900 and is formed by the amide linkage of β-alanine and L-histidine. Carnosine production is limited by β-alanine whereas the imidazole ring of histidine moiety makes it a suitable buffer in physiological pH range. It is reported to be found in the skeletal muscle, brain, heart, and gastrointestinal tissues of humans. This review focuses on the biological properties of carnosine including pH buffering ability, antioxidant activity, anti-inflammatory activity, anti-aging effect, enhancement of cognitive function, and immunomodulation. The relevance of carnosine in muscle function attributing to enhancement of physical performance has also been highlighted. Studies spanning several years have proved the preclinical effectiveness of carnosine in treating diverse pathological diseases. A complete summary of all key activities of carnosine from in vivo investigations and clinical trials has been compiled. Considering its numerous advantages, carnosine may be a promising option for the development of a nutraceutical.

Abscopal effect: from a rare phenomenon to a new frontier in cancer therapy

Radiotherapy (RT) controls local lesions, meantime it has the capability to induce systemic response to inhibit distant, metastatic, non-radiated tumors, which is referred to as the "abscopal effect". It is widely recognized that radiotherapy can stimulate systemic immune response. This provides a compelling theoretical basis for the combination of immune therapy combined with radiotherapy(iRT). Indeed, this phenomenon has also been observed in clinical treatment, bringing significant clinical benefits to patients, and a series of basic studies are underway to amplify this effect. However, the molecular mechanisms of immune response induced by RT, determination of the optimal treatment regimen for iRT, and how to amplify the abscopal effect. In order to amplify and utilize this effect in clinical management, these key issues require to be well addressed; In this review, we comprehensively summarize the growing consensus and emphasize the emerging limitations of enhancing the abscopal effect with radiotherapy or immunotherapy. Finally, we discuss the prospects and barriers to the current clinical translational applications.

Zinc supplementation for dysgeusia in patients with unresectable pancreatic cancer

BACKGROUND

Although patients with advanced pancreatic cancer (PC) often experience dysgeusia with zinc deficiency during chemotherapy, data on zinc supplementation for dysgeusia and its effects on nutritional status are scarce. We aimed to examine the efficacy of zinc supplementation in patients with advanced PC.

METHODS

Thirty-three patients with unresectable PC who presented with dysgeusia and zinc deficiency during chemotherapy and received zinc acetate hydrate between January 2018 and December 2022 were included. We evaluated the changes in serum zinc levels and the improvement in dysgeusia. Among the 26 patients who received zinc supplementation for 12 weeks, we also compared patient characteristics and changes in serum zinc and albumin levels between patients who showed improvement in dysgeusia (effective group) and those who did not (non-effective group).

RESULTS

The serum zinc level increased significantly after zinc supplementation (median: 60 µg/dL at baseline, 99.5 µg/dL at 4 weeks, 101 µg/dL at 8 weeks and 101 µg/dL at 12 weeks). The rate of improvement in dysgeusia increased over time (18.2% at 4 weeks, 33.3% at 8 weeks, and 42.4% at 12 weeks). Comparing the effective group and non-effective group revealed that while the median serum albumin level of the effective group did not change, the non-effective group showed a significant decrease from baseline to 12 weeks (3.2 g/dL to 3.0 g/dL, p = 0.03).

CONCLUSION

Zinc supplementation significantly increased serum zinc levels, improving dysgeusia. Zinc supplementation might also contribute to maintaining nutritional status in patients with unresectable PC.

An unmet need for pharmacology: Treatments for radiation-induced gastrointestinal mucositis

Gastrointestinal mucositis (GIM) continues to be a significant issue in the management of abdominal cancer radiation treatments and chemotherapy, causing significant patient discomfort and therapy interruption or even cessation. This review will first focus on radiotherapy induced GIM, providing an understanding of its clinical landscape. Subsequently, the aetiology of GIM will be reviewed, highlighting diverse contributing factors. The cellular and tissue damage and associated molecular responses in GIM will be summarised in the context of the underlying complex biological processes. Finally, available drugs and pharmaceutical therapies will be evaluated, underscoring their insufficiency, and highlighting the need for further research and innovation. This review will emphasize the urgent need for improved pharmacologic therapeutics for GIM, which is a key research priority in oncology.

The microbiota-gut-brain-immune interface in the pathogenesis of neuroinflammatory diseases: a narrative review of the emerging literature

Importance

Research is beginning to elucidate the sophisticated mechanisms underlying the microbiota-gut-brain-immune interface, moving from primarily animal models to human studies. Findings support the dynamic relationships between the gut microbiota as an ecosystem (microbiome) within an ecosystem (host) and its intersection with the host immune and nervous systems. Adding this to the effects on epigenetic regulation of gene expression further complicates and strengthens the response. At the heart is inflammation, which manifests in a variety of pathologies including neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, and Multiple Sclerosis (MS).

Observations

Generally, the research to date is limited and has focused on bacteria, likely due to the simplicity and cost-effectiveness of 16s rRNA sequencing, despite its lower resolution and inability to determine functional ability/alterations. However, this omits all other microbiota including fungi, viruses, and phages, which are emerging as key members of the human microbiome. Much of the research has been done in pre-clinical models and/or in small human studies in more developed parts of the world. The relationships observed are promising but cannot be considered reliable or generalizable at this time. Specifically, causal relationships cannot be determined currently. More research has been done in Alzheimer's disease, followed by Parkinson's disease, and then little in MS. The data for MS is encouraging despite this.

Conclusions and relevance

While the research is still nascent, the microbiota-gut-brain-immune interface may be a missing link, which has hampered our progress on understanding, let alone preventing, managing, or putting into remission neurodegenerative diseases. Relationships must first be established in humans, as animal models have been shown to poorly translate to complex human physiology and environments, especially when investigating the human gut microbiome and its relationships where animal models are often overly simplistic. Only then can robust research be conducted in humans and using mechanistic model systems.

Expression analysis of zinc-metabolizing enzymes in the saliva as a new method of evaluating zinc content in the body: two case reports and a review of the literature

BACKGROUND

The activity level of alkaline phosphatase, a zinc-requiring enzyme in the serum, is used to indicate zinc nutritional status; however, it does not correlate with serum zinc levels or subjective symptoms of taste disorder in many cases. Hence, this study focused on the total activity of alkaline phosphatase, a zinc-requiring enzyme. The total alkaline phosphatasa activity level in the saliva was measured before and after zinc supplementation, and the results were compared with serum zinc levels.

CASE PRESENTATION

This study included patients with hypozincemia, specifically a patient with zinc-deficient taste disorder (patient 1: a 69-year-old Japanese woman) and a patient with glossodynia with zinc deficiency (patient 2: an 82-year-old Japanese woman). Saliva samples were collected, and blood tests were performed before and after zinc supplementation. Subjective symptoms and serum zinc levels were simultaneously evaluated. Zinc supplementation was performed using zinc acetate hydrate or Polaprezinc.

CONCLUSIONS

Total alkaline phosphatase activity levels were found to be associated with serum zinc levels and subjective symptoms. A further study with a higher number of patients is necessary to confirm whether total alkaline phosphatase activity levels more accurately reflect the amounts of zinc in the body than serum zinc levels.

Cross-sectional observational study: Investigation of zinc concentration in white patients with cancer

OBJECTIVES

Numerous studies describe the role of zinc in the immune system and metabolism. Zinc may influence the pathogenesis and prognosis of cancer. The aim of this study to determine the prevalence of zinc deficiency in patients with cancer. The study's primary objective was to evaluate the frequency of zinc deficiency in White patients with cancer and characterize the clinical factors predisposing individuals to decreased zinc concentration. The study also aimed to estimate the dose of zinc supplementation that would prevent deficiency.

METHODS

Retrospective data for this cross-sectional study were analyzed from 300 consecutive white patients diagnosed with neoplastic disease and admitted to a major oncology hospital for treatment. Zinc plasma concentration, nutritional status, body composition, and medical history of ailments and dysphagia were recorded. Supplementation was introduced in patients with zinc deficiency according to the local protocol. Zinc plasma levels were collected at follow-up visits.

RESULTS

Zinc deficiency was diagnosed in 68% of the patients. Poor nutritional status was significantly associated with zinc deficiency (low body mass index, weight loss, low albumin level). Low lean body mass (P = 0.003) and adipose tissue (P = 0.045) correlated with zinc deficiency. Patients with zinc deficiency reported dysphagia more frequently than those with normal zinc levels (18 versus 8%; P = 0.03). Squamous cell carcinoma was significantly associated with zinc deficiency (P = 0.043). Oral zinc supplementation resulted in reaching laboratory norms for plasma concentration in only 27% of patients with zinc deficiency and was not dependent on lower (10-15 mg) or higher (25-30 mg) dosing (P > 0.05).

CONCLUSIONS

Zinc deficiency is common in cachectic, malnourished patients with cancer. Nutritional guidelines for these patients should include screening for micronutrient deficiencies. Further studies are needed to determine the role, dosage, duration, and form of nutritional supplementation recommended for specific cancer diagnoses.

Antioxidant peptides, the guardian of life from oxidative stress

Reactive oxygen species (ROS) are produced during oxidative metabolism in aerobic organisms. Under normal conditions, ROS production and elimination are in a relatively balanced state. However, under internal or external environmental stress, such as high glucose levels or UV radiation, ROS production can increase significantly, leading to oxidative stress. Excess ROS production not only damages biomolecules but is also closely associated with the pathogenesis of many diseases, such as skin photoaging, diabetes, and cancer. Antioxidant peptides (AOPs) are naturally occurring or artificially designed peptides that can reduce the levels of ROS and other pro-oxidants, thus showing great potential in the treatment of oxidative stress-related diseases. In this review, we discussed ROS production and its role in inducing oxidative stress-related diseases in humans. Additionally, we discussed the sources, mechanism of action, and evaluation methods of AOPs and provided directions for future studies on AOPs.

Electrophoretic Determination of L-Carnosine in Health Supplements Using an Integrated Lab-on-a-Chip Platform with Contactless Conductivity Detection

The health supplement industry is one of the fastest growing industries in the world, but there is a lack of suitable analytical methods for the determination of active compounds in health supplements such as peptides. The present work describes an implementation of contactless conductivity detection on microchip technology as a new strategy for the electrophoretic determination of L-carnosine in complex health supplement formulations without pre-concentration and derivatization steps. The best results were obtained in the case of +1.00 kV applied for 20 s for injection and +2.75 kV applied for 260 s for the separation step. Under the selected conditions, a linear detector response of 5 × 10-6 to 5 × 10-5 M was achieved. L-carnosine retention time was 61 s. The excellent reproducibility of both migration time and detector response confirmed the high precision of the method. The applicability of the method was demonstrated by the determination of L-carnosine in three different samples of health supplements. The recoveries ranged from 91 to 105%. Subsequent analysis of the samples by CE-UV-VIS and HPLC-DAD confirmed the accuracy of the obtained results.

Association between serum trace elements and sleep disturbance in patients with decompensated cirrhosis

Background

Sleep disturbance and trace elements imbalance are common features in patients with decompensated cirrhosis, partially sharing similar mechanistic contributors and linking to adverse outcomes. However, there is a paucity of data concerning their relationship.

Objectives

To investigate the association between serum trace elements levels and sleep quality in the context of cirrhosis.

Design

Cross-sectional study.

Methods

We consecutively enrolled 160 patients with decompensated cirrhosis. The sleep disturbance was determined by the Pittsburgh Sleep Quality Index (PSQI > 5). Serum trace elements [magnesium, calcium, iron, copper (Cu), zinc (Zn), lead, and manganese] was measured by inductively coupled plasma mass spectrometry. Association of examined trace elements levels and sleep disturbance was analyzed by multiple linear (global PSQI scores) and multivariate logistic (dichotomized PSQI categories) regression models, respectively.

Results

In total, 91 patients (56.88%) represented PSQI-defined sleep disturbance, characterized by female preponderance, lower body mass index levels, and higher serum Cu levels (all p < 0.05). Looking into its clinical relevance with debilitating conditions, we showed that Cu/Zn ratio (CZr) is significantly higher in cirrhosis with poor sleep quality (1.77 versus 1.48, p = 0.003). Diagnostic performance analysis indicated CZr > 1.62 to exhibit better discrimination relative to respective Cu. Both multiple linear (β = 0.355, p < 0.001) and multivariate logistic regression (odds ratio = 2.364, p = 0.019) identified higher CZr as an independent risk factor associated with sleep disturbance.

Conclusion

Our findings implied an association between higher CZr and the presence of sleep disturbance in patients with decompensated cirrhosis.

The Effect of a Zinc-L-Carnosine Mouthwash in the Management of Oral Surgical Wounds: Preliminary Results of a Prospective Cohort Study

BACKGROUND

Zinc L-carnosine promotes the transition from the inflammatory to the proliferative phase of wound healing by reducing the expression of pro-inflammatory signals and enhancing the expression of anti-inflammatory signals. This prospective cohort study aims to test the effect of a zinc-L-carnosine mouthwash in promoting oral surgical wound healing.

METHODS

From October 2022 to February 2023, the authors enrolled healthy adult volunteers who needed the extraction of bilateral molars at the Unit of Dentistry of the University of Bari. The authors studied the baseline wound healing of each patient after the first extraction. Three months later, the patients underwent the second extraction and rinsed their mouths with zinc-L-carnosine mouthwash twice per day for the following 28 postoperative days. For a month after each extraction, the patients received weekly follow-up visits by an oral surgeon blinded about the study to record the modified healing index score of the wounds (range 0-6 points). For statistical analysis, we used the one-tailed t-test for paired samples with a significance level set at p < 0.05 to compare the baseline scores with those recorded during the exposure to the zinc-L-carnosine mouthwash.

RESULTS

The authors enrolled four women and six men (mean age = 44.60 ± 19.22 years). On the seventh and fourteenth postoperative days, the mean difference between the modified healing index scores obtained by using the zinc-L-carnosine mouthwash and the baseline was not significant. On the twenty-first postoperative day, the mean score obtained by using the mouthwash was 5.2 ± 1.3 points and was significantly higher than the 4.7 ± 1.8 points of the baseline (p = 0.026). On the twenty-eighth postoperative day, the mean difference was significant as well (5.9 ± 0.3 points and 5.4 ± 1.1 points, respectively).

CONCLUSION

The preliminary results of this study showed that the zinc-L-carnosine mouthwash improved the quality of oral surgical wound healing.

Therapeutic Effect of Polaprezinc on Reflux Esophagitis in the Rat Model

BACKGROUND/AIMS

To explore the protective effects and therapeutic mechanism of Esomeprazole (PPI), polaprezinc granule (PZ), and PPI + PZ on reflux esophagitis (RE) in the rat model.

METHODS

Wistar rats were randomly divided into 9 groups, which contain the control group, the acid cessation group (0.7% HCl, Q3D × 4), and the acid persistence group (0.7% HCl, Q3D × 11). PPI was administered by gavage at 8 mg·kg^-1 body weight and PZ was administered by gavage at 120 mg·kg^-1 body weight once a day for 15 days. The gastric cardia tissue of the feeding tube was observed under the light microscope, and the levels of interleukin-8 (IL-8) and prostaglandin E2 (PGE2) were measured by ELISA. The expression of EGFR, Akt, p-Akt, and p-mTOR was detected by Western blot.

RESULTS

The ELISA results showed that the levels of IL-8 and PGE2 were significantly increased in the model group, but decreased in all groups after treatment. In the acid cessation group, PZ treatment had the most significant effect on reducing IL-8 levels and PPI + PZ treatment had the most significant effect on reducing PGE2 levels. In the acid persistence group, the PPI treatment had the most significant effect on reducing the levels of IL-8 and PGE2, and the PZ treatment could also significantly reduce their levels, close to the normal value. Western blot results showed that the expression of PI3K/Akt/mTOR pathway protein was increased in the model group, while its expression was decreased after treatment.

CONCLUSIONS

Polaprezinc has a significant therapeutic effect on RE in rats, which can reduce the levels of IL-8 and PGE2 and downregulate the expression of PI3K/Akt/mTOR signal pathway protein. The efficacy of polaprezinc in the treatment of reflux esophagitis is comparable to that of PPI, and the combination of them is more effective in the reflux esophagitis treatment.

Nano shield: a new tetrahedral framework nucleic acids-based solution to radiation-induced mucositis

Radiation-induced oral mucositis (RIOM) is considered to be one of the most important public health problems today, affecting the overall well-being of millions of patients who have received radiotherapy. Nevertheless, the field of preventing and treating RIOM is still widely unexplored. Curcumin (Cur) with its promising anti-inflammatory and antioxidant properties is accompanied with obstacles in application, including poor dissolubility, instability and low bioavailability. In this study, a tetrahedral framework nucleic acid drug delivery system (TFNAS) was synthesized and established using a novel method to carry Cur (Cur-TFNAS) for efficient drug delivery. The results showed that Cur-TFNAS enhanced the antioxidant capacity of human oral mucosal keratin-forming cells (HOKs) compared to free Cur and TFNAS. Meanwhile, Cur-TFNAS reduced DNA damage and shielded the cells from inflammatory factors. A similar result was also well documented in vivo. Herein, we consider that Cur-TFNAS acts as a nano-shield for preventing radiation oral mucositis and shows important clinical value in the future.

Heat shock protein 70 is involved in polaprezinc driven cell protection against Helicobacter pylori-induced injury

Polaprezinc (PZ) plays a role in the protection of gastric mucosa and inhibiting Helicobacter pylori (H. pylori) growth in vitro. The objective of this study was to determine the protective effects of PZ on human gastric epithelial cells (GES-1) against H. pylori-induced damage, while also examining heat shock protein 70 (HSP70) as a potential underlying factor in this protection. Our findings revealed that PZ exerted bactericidal effects against H. pylori strains. We also observed that PZ mitigated the H. pylori-induced damage to GES-1 cells by increasing cell viability, reducing LDH release, and decreasing the secretion of pro-inflammatory factors such as MCP-1 and IL-6. Co-culturing PZ with GES-1 cells significantly up-regulated the GES-1 HSP70 expression in both a time and dose-dependent manner. Pre-incubating (for 12 h) or co-culturing (for 24 h) GES-1 cells with PZ reversed the down-regulation of HSP70 in GES-1 cells caused by H. pylori infection. However, when quercetin was used to inhibit the up-regulation of HSP70 in GES-1 cells, the protective effect of PZ on GES-1 cells was significantly reduced. Based on the results of this study, PZ exhibits a protective role on GES-1 cells against H. pylori injury, as well as a direct bactericidal effect on H. pylori. HSP70 is involved in the PZ-driven host cell protection against H. pylori injury. These findings provide insight into alternative strategies for H. pylori treatment.

Carnosine and Beta-Alanine Supplementation in Human Medicine: Narrative Review and Critical Assessment

The dipeptide carnosine is a physiologically important molecule in the human body, commonly found in skeletal muscle and brain tissue. Beta-alanine is a limiting precursor of carnosine and is among the most used sports supplements for improving athletic performance. However, carnosine, its metabolite N-acetylcarnosine, and the synthetic derivative zinc-L-carnosine have recently been gaining popularity as supplements in human medicine. These molecules have a wide range of effects—principally with anti-inflammatory, antioxidant, antiglycation, anticarbonylation, calcium-regulatory, immunomodulatory and chelating properties. This review discusses results from recent studies focusing on the impact of this supplementation in several areas of human medicine. We queried PubMed, Web of Science, the National Library of Medicine and the Cochrane Library, employing a search strategy using database-specific keywords. Evidence showed that the supplementation had a beneficial impact in the prevention of sarcopenia, the preservation of cognitive abilities and the improvement of neurodegenerative disorders. Furthermore, the improvement of diabetes mellitus parameters and symptoms of oral mucositis was seen, as well as the regression of esophagitis and taste disorders after chemotherapy, the protection of the gastrointestinal mucosa and the support of Helicobacter pylori eradication treatment. However, in the areas of senile cataracts, cardiovascular disease, schizophrenia and autistic disorders, the results are inconclusive.

Gap Junctions and Connexins in Microglia-Related Oxidative Stress and Neuroinflammation: Perspectives for Drug Discovery

Microglia represent the immune system of the brain. Their role is central in two phenomena, neuroinflammation and oxidative stress, which are at the roots of different pathologies related to the central nervous system (CNS). In order to maintain the homeostasis of the brain and re-establish the equilibrium after a threatening imbalance, microglia communicate with each other and other cells within the CNS by receiving specific signals through membrane-bound receptors and then releasing neurotrophic factors into either the extracellular milieu or directly into the cytoplasm of nearby cells, such as astrocytes and neurons. These last two mechanisms rely on the activity of protein structures that enable the formation of channels in the membrane, namely, connexins and pannexins, that group and form gap junctions, hemichannels, and pannexons. These channels allow the release of gliotransmitters, such as adenosine triphosphate (ATP) and glutamate, together with calcium ion (Ca2+), that seem to play a pivotal role in inter-cellular communication. The aim of the present review is focused on the physiology of channel protein complexes and their contribution to neuroinflammatory and oxidative stress-related phenomena, which play a central role in neurodegenerative disorders. We will then discuss how pharmacological modulation of these channels can impact neuroinflammatory phenomena and hypothesize that currently available nutraceuticals, such as carnosine and N-acetylcysteine, can modulate the activity of connexins and pannexins in microglial cells and reduce oxidative stress in neurodegenerative disorders.

Cytoskeletal Responses and Aif-1 Expression in Caco-2 Monolayers Exposed to Phorbol-12-Myristate-13-Acetate and Carnosine

The dis(re)organization of the cytoskeletal actin in enterocytes mediates epithelial barrier dys(re)function, playing a key role in modulating epithelial monolayer's integrity and remodeling under transition from physiological to pathological states. Here, by fluorescence-based morphological and morphometric analyses, we detected differential responses of cytoskeletal actin in intestinal epithelial Caco-2 cell monolayers at two different stages of their spontaneous differentiation, i.e., undifferentiated cells at 7 days post-seeding (dps) and differentiated enterocyte-like cells at 21 dps, upon challenge in vitro with the inflammation-mimicking stimulus of phorbol-12-myristate-13-acetate (PMA). In addition, specific responses were found in the presence of the natural dipeptide carnosine detecting its potential counteraction against PMA-induced cytoskeletal alterations and remodeling in differentiated Caco-2 monolayers. In such an experimental context, by both immunocytochemistry and Western blot assays in Caco-2 monolayers, we identified the expression of the allograft inflammatory factor 1 (AIF-1) as protein functionally related to both inflammatory and cytoskeletal pathways. In 21 dps monolayers, particularly, we detected variations of its intracellular localization associated with the inflammatory stimulus and its mRNA/protein increase associated with the differentiated 21 dps enterocyte-like monolayer compared to the undifferentiated cells.

Expression profile of the zinc transporter ZnT3 in taste cells of rat circumvallate papillae and its role in zinc release, a potential mechanism for taste stimulation

Zinc is an essential trace element, and its deficiency causes taste dysfunction. Zinc accumulates in zinc transporter (ZnT)3-expressing presynaptic vesicles in hippocampal neurons and acts as a neurotransmitter in the central nervous system. However, the distribution of zinc and its role as a signal transmitter in taste buds remain unknown. Therefore, we examined the distribution of zinc and expression profiles of ZnT3 in taste cells and evaluated zinc release from isolated taste cells upon taste stimuli. Taste cells with a spindle or pyriform morphology were revealed by staining with the fluorescent zinc dye ZnAF-2DA and autometallography in the taste buds of rat circumvallate papillae. Znt3 mRNA levels were detected in isolated taste buds. ZnT3-immunoreactivity was found in phospholipase-β2-immunopositive type II taste cells and aromatic amino acid decarboxylase-immunopositive type III cells but not in nucleoside triphosphate diphosphohydrolase 2-immunopositive type I cells. Moreover, we examined zinc release from taste cells using human transient receptor potential A1-overexpressing HEK293 as zinc-sensor cells. These cells exhibited a clear response to isolated taste cells exposed to taste stimuli. However, pretreatment with magnesium-ethylenediaminetetraacetic acid, an extracellular zinc chelator - but not with zinc-ethylenediaminetetraacetic acid, used as a negative control - significantly decreased the response ratio of zinc-sensor cells. These findings suggest that taste cells release zinc to the intercellular area in response to taste stimuli and that zinc may affect signaling within taste buds.

Efficacy and Safety of Polaprezinc-Based Therapy versus the Standard Triple Therapy for Helicobacter pylori Eradication: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Helicobacter pylori (H. pylori) is the most prevalent etiology of gastritis worldwide. H. pylori management depends mainly on antibiotics, especially the triple therapy formed of clarithromycin, amoxicillin, and proton pump inhibitors. Lately, many antibiotic-resistant strains have emerged, leading to a decrease in the eradication rates of H. pylori. Polaprezinc (PZN), a mucosal protective zinc-L-carnosine complex, may be a non-antibiotic agent to treat H. pylori without the risk of resistance. We performed a systematic review and meta-analysis to evaluate the efficacy and safety of a PZN-based regimen for the eradication of H. pylori. This study used a systematic review and meta-analysis synthesizing randomized controlled trials (RCTs) from WOS, SCOPUS, EMBASE, PubMed, and Google Scholar until 25 July 2022. We used the odds ratio (OR) for dichotomous outcomes presented with the corresponding 95% confidence interval (CI). We registered our protocol in PROSPERO with ID: CRD42022349231. We included 3 trials with a total of 396 participants who were randomized to either PZN plus triple therapy (n = 199) or triple therapy alone (control) (n = 197). Pooled OR found a statistical difference favoring the PZN arm in the intention to treat and per protocol H. pylori eradication rates (OR: 2.01 with 95% CI [1.27, 3.21], p = 0.003) and (OR: 2.65 with 95% CI [1.55, 4.54], p = 0.0004), respectively. We found no statistical difference between the two groups regarding the total adverse events (OR: 1.06 with 95% CI [0.55, 2.06], p = 0.85). PZN, when added to the triple therapy, yielded a better effect concerning the eradication rates of H. pylori with no difference in adverse event rates, and thus can be considered a valuable adjuvant for the management of H. pylori. However, the evidence is still scarce, and larger trials are needed to confirm or refute our findings.

The role of Zinc L-Carnosine in the prevention and treatment of gastrointestinal mucosal disease in humans: a review

Zinc L-carnosine is a pharmaceutical compound with direct mucosal cytoprotective and anti-inflammatory action through its antioxidative effects, cytokine modulation and membrane-stabilizing properties. Chemically, it is not an anti-secretory, antacid or raft-forming agent; its properties are mainly mediated by its higher affinity for damaged mucosa that permits the release of zinc locally by ligand exchange. Beneficial effects on various types of mucosal damage have been described in vitro and in vivo, in both animals and humans. It has been shown to promote repair of mucosal injury in human studies and has been widely used for the treatment of peptic ulcers, chemoradiotherapy-induced oral mucositis and esophagitis. More recently, the therapeutic applications of Zinc L-carnosine have been extended to the prevention and cure of various types of intestinal damage, including ulcerative colitis, iatrogenic ulcers after operative endoscopy, hemorrhoidal disease and impaired intestinal permeability. This review concentrates mainly on the current and future applications of zinc L-carnosine in gastrointestinal disease, and may be of use to gastroenterologists and endoscopists. It describes the therapeutic principles and benefits of this interesting molecule and discusses the potential future fields of interest for clinical use in humans.

Zinc carnosine: Frontiers advances of supplement for cancer therapy

Zinc (Zn) has an existence within large quantities in the human brain, while accumulating within synaptic vesicle. There is growing evidence that Zn metabolic equilibrium breaking participates into different diseases (e.g., vascular dementia, carcinoma, Alzheimer's disease). Carnosine refers to an endogenic dipeptide abundant in skeletal muscle and brains and exerts a variety of positive influences (e.g., carcinoma resistance, crosslinking resistance, metal chelation and oxidation limitation). A complex of Zn and carnosine, called Zinc-L-carnosine (ZnC), has been extensively employed within Zn supplement therapeutic method and the treating approach for ulcers. ZnC has been shown to play a variety of roles in the body, including inhibiting intracellular reactive oxygen species(ROS) and free radical levels, inhibiting inflammation, supplementing zinc enzymes and promoting wound healing and mucosal cell repair. The present study conducting a reviewing process for the advances of ZnC in tumor adjuvant therapy.

Mucosal Overexpression of Thymic Stromal Lymphopoietin and Proinflammatory Cytokines in Patients With Autoimmune Atrophic Gastritis

INTRODUCTION

The immune mechanisms underlying human autoimmune atrophic gastritis (AAG) are poorly understood. We sought to assess immune mucosal alterations in patients with AAG.

METHODS

In 2017-2021, we collected gastric corpus biopsies from 24 patients with AAG (median age 62 years, interquartile range 56-67, 14 women), 26 age-matched and sex-matched healthy controls (HCs), and 14 patients with Helicobacter pylori infection (HP). We investigated the lamina propria mononuclear cell (LPMC) populations and the mucosal expression of thymic stromal lymphopoietin (TSLP) and nicotinamide phosphoribosyltransferase (NAMPT). Ex vivo cytokine production by organ culture biopsies, under different stimuli (short TSLP and zinc-l-carnosine), and the gastric vascular barrier through plasmalemma vesicle-associated protein-1 (PV1) were also assessed.

RESULTS

In the subset of CD19+ LPMC, CD38+ cells (plasma cells) were significantly higher in AAG compared with HC. Ex vivo production of tumor necrosis factor (TNF)-α, interleukin (IL)-15, and transforming growth factor β1 was significantly higher in AAG compared with HC. At immunofluorescence, both IL-7R and TSLP were more expressed in AAG compared with HC and HP, and short TSLP transcripts were significantly increased in AAG compared with HC. In the supernatants of AAG corpus mucosa, short TSLP significantly reduced TNF-α, while zinc-l-carnosine significantly reduced interferon-γ, TNF-α, IL-21, IL-6, and IL-15. NAMPT transcripts were significantly increased in AAG compared with HC. PV1 was almost absent in AAG, mildly expressed in HC, and overexpressed in HP.

DISCUSSION

Plasma cells, proinflammatory cytokines, and altered gastric vascular barrier may play a major role in AAG. TSLP and NAMPT may represent potential therapeutic targets, while zinc-l-carnosine may dampen mucosal inflammation.

Drug repositioning of polaprezinc for bone fracture healing

Fractures and related complications are a common challenge in the field of skeletal tissue engineering. Vitamin D and calcium are the only broadly available medications for fracture healing, while zinc has been recognized as a nutritional supplement for healthy bones. Here, we aimed to use polaprezinc, an anti-ulcer drug and a chelate form of zinc and L-carnosine, as a supplement for fracture healing. Polaprezinc induced upregulation of osteogenesis-related genes and enhanced the osteogenic potential of human bone marrow-derived mesenchymal stem cells and osteoclast differentiation potential of mouse bone marrow-derived monocytes. In mouse experimental models with bone fractures, oral administration of polaprezinc accelerated fracture healing and maintained a high number of both osteoblasts and osteoclasts in the fracture areas. Collectively, polaprezinc promotes the fracture healing process efficiently by enhancing the activity of both osteoblasts and osteoclasts. Therefore, we suggest that drug repositioning of polaprezinc would be helpful for patients with fractures.

Polaprezinc promoted both osteoblast and osteoclast differentiation and altered YAP protein expression in vitro, and animals treated with polaprezinc showed greater bone formation in their fracture calluses after 21 days.

Antioxidant and Neuroprotective Effects of Carnosine: Therapeutic Implications in Neurodegenerative Diseases

Neurodegenerative diseases (NDs) constitute a global challenge to human health and an important social and economic burden worldwide, mainly due to their growing prevalence in an aging population and to their associated disabilities. Despite their differences at the clinical level, NDs share fundamental pathological mechanisms such as abnormal protein deposition, intracellular Ca²⁺ overload, mitochondrial dysfunction, redox homeostasis imbalance and neuroinflammation. Although important progress is being made in deciphering the mechanisms underlying NDs, the availability of effective therapies is still scarce. Carnosine is a natural endogenous molecule that has been extensively studied during the last years due to its promising beneficial effects for human health. It presents multimodal mechanisms of action, being able to exert antioxidant, anti-inflammatory and anti-aggregate activities, among others. Interestingly, most NDs exhibit oxidative and nitrosative stress, protein aggregation and inflammation as molecular hallmarks. In this review, we discuss the neuroprotective functions of carnosine and its implications as a therapeutic strategy in different NDs. We summarize the existing works that study alterations in carnosine metabolism in Alzheimer’s disease and Parkinson’s disease, the two most common NDs. In addition, we review the beneficial effect that carnosine supplementation presents in models of such diseases as well as in aging-related neurodegeneration.

Effectiveness of sodium bicarbonate and zinc chloride mouthwashes in the treatment of oral mucositis and quality of life in patients with cancer under chemotherapy

Aim

The purpose of the study is to evaluate the effectiveness of sodium bicarbonate and zinc chloride mouthwashes on oral mucositis and quality of life in patients undergoing chemotherapy.

Design

The present study was a randomized controlled trial study.

Methods

One hundred forty‐four patients with a cancer diagnosis were randomly assigned into three groups: sodium bicarbonate mouthwash (n = 48), zinc chloride mouthwash (n = 48) and placebo group (n = 48). The severity of mucositis and quality of life were examined blindly at the baseline and 3‐week follow‐up.

Results

The grade of oral mucositis decreased at the end of the third weeks in the sodium bicarbonate and zinc chloride groups rather than the placebo group (p < .001). The severity of oral mucositis in the sodium bicarbonate and zinc chloride groups decreased from end of the first week until third week (p < .001). In addition, there was significant difference in the severity of oral mucositis among the groups at the end of the second (p = .014) and the third weeks (p < .001). Also, there was a statistically significant difference in quality of life scores between the sodium bicarbonate and zinc chloride mouthwash with the placebo group (p < .001).

Conclusion

Zinc chloride and sodium bicarbonate mouthwashes were effective in treating and reducing the severity of oral mucositis, and subsequently improving quality of life in patients with cancer under chemotherapy. Therefore, we can recommend zinc chloride and sodium bicarbonate at the beginning of chemotherapy to improve oral health and promoting quality of life in these patients.

Study on the Local Anti-Osteoporosis Effect of Polaprezinc-Loaded Antioxidant Electrospun Membrane

Background

Compared with the healthy condition, osteoporotic bone defects are often accompanied by poor osteogenesis and excessive reactive oxygen species (ROS), which pose serious challenges to bone augmentation and repair by normal resorbable guided bone regeneration (GBR) membrane.

Purpose

Polaprezinc (PZ) was loaded into polycaprolactone/gelatin (PG) hybrid electrospun nanofibers to fabricate a GBR membrane with antioxidant and osteogenesis ability.

Methods

A series of physicochemical characterization were performed by scanning electron microscopy, Fourier-transform infrared spectroscopy, and water contact angle measurement. In addition to membrane degradation and PZ release detection, membranes were tested for cell viability, differentiation, and protein expression in MC3T3-E1 cells by CCK8, alkaline phosphatase activity, mineralization, and Western blotting assays. The membrane osteogenic capacity in cranial bone defects was studied by micro-CT in vivo.

Results

PZ was successfully doped into the PCL/GEL nanofibers to form a hydrophilic GBR membrane. The cumulative release of PZ was closely related to the membrane degradation behavior. PG/0.4%PZ membranes produced the best protective effect on cell proliferation/differentiation under oxidative stress microenvironment; however, the PG/0.8%PZ membrane was cytotoxic. Western blotting demonstrated that the PZ-loaded membrane upregulated the Nrf2/HO-1/SOD1 signaling molecules in a concentration-dependent manner. In addition, micro-CT results showed an abundant formation of new bones in the PG/0.4%PZ group compared to the PG group.

Conclusion

PZ-loaded degradable PG membranes (especially PG/0.4%PZ) have great potential to accelerate bone regeneration in oxidative stress-related diseases.

Zinc carnosine-based modified bismuth quadruple therapy vs standard triple therapy for Helicobacter pylori eradication: A randomized controlled study

BACKGROUND

Helicobacter pylori (H. pylori) infection is a worldwide problem with increasing burden on the health sector due to its increasing rate of resistance. The conventional triple therapy (TT) is becoming obsolete with a high failure rate of eradication, necessitating the need for better alternatives or regimens.

AIM

To investigate H. pylori eradication rate of TT vs modified bismuth quadruple therapy.

METHODS

Ninety-two patients with dyspepsia symptoms and positive ¹³C-urea breath test were randomly assigned to two groups. The first group (control group) was treated for 14 d using standard TT protocol: Esomeprazole (40 mg twice daily), amoxicillin (1 g twice daily) and clarithromycin (500 mg twice daily). On the other hand, the second group was prescribed a 10-d course of modified bismuth quadruple therapy fortified with zinc carnosine: TT in addition to bismuth subcitrate (240 mg twice daily) and zinc carnosine (75 mg twice daily). A repeated ¹³C-urea breath test was done 4 wk after the completion of the eradication therapy.

RESULTS

Among the 92 subjects, 67.4% were males and 32.6% were females. There were no differences in demographic characteristics (age, body mass index, smoking history, previous antibiotics use and ethnicity) between the modified bismuth quadruple therapy group and TT group. The eradication rate was higher [93.5% (43/46)] in the modified bismuth quadruple therapy group compared to 69.6% (32/46) in the standard TT group (P = 0.003). Of the tested predictor variables, only nationality, smoking and therapy type were statistically significant. Besides dizziness, which was recorded in modified bismuth quadruple therapy group, there were no significant differences in side effects between the two groups.

CONCLUSION

Ten days of modified bismuth quadruple therapy fortified with zinc carnosine is superior to 14 d of conventional TT in eradicating H. pylori infection, with no additional significant adverse events.

Zinc Acetate Dihydrate Tablet-associated Gastric Lesions

Objective This study aimed to determine the prevalence and endoscopic features of zinc acetate dihydrate tablet-associated gastric lesions. Methods We retrospectively examined the endoscopic features of 47 patients taking zinc acetate dihydrate tablets who underwent esophagogastroduodenoscopy. Results Gastric mucosal alterations, including redness, erosions, ulcers, and adhesion of the white coat, were observed in 29 of 47 patients (61.7%). Among patients with gastric lesions (group A), there was a significantly higher percentage of symptomatic patients in comparison to patients without lesions (group B) (65.5% vs. 22.2%; p<0.01). The background characteristics of the two groups did not differ to a statistically significant extent. On esophagogastroduodenoscopy, mucosal redness (n=27, 93.1%), erosions (n=26, 90.0%), adhesion of the white coat (n=25, 86.2%), and ulcers (n=9, 31.0%) were observed. None of the 19 patients who previously underwent esophagogastroduodenoscopy had gastric lesions before starting zinc acetate dihydrate. Esophagogastroduodenoscopy was performed after the cessation of zinc acetate dihydrate intake in six patients, and revealed the resolution of gastric lesions. Conclusion Gastric lesions were observed in 29 of 47 patients who were taking zinc acetate dihydrate tablets. The most common endoscopic findings were mucosal redness (93.1%), erosions (90.0%), adhesion of the white coat (86.2%), and ulcers (31.0%). Although the exact pathogenesis is uncertain, we believe that understanding the unique manifestations of this gastric lesion will help physicians manage adverse events in patients taking zinc acetate dihydrate tablets.

Managing Severe Dysgeusia and Dysosmia in Lung Cancer Patients: A Systematic Scoping Review

Introduction

Lung cancer (LC) is highly prevalent worldwide, with elevated mortality. In this population, taste and smell alterations (TSAs) are frequent but overlooked symptoms. The absence of effective therapeutic strategies and evidence-based guidelines constrain TSAs’ early recognition, prevention and treatment (Tx), promoting cancer-related malnutrition and jeopardizing survival outcomes and quality of life.

Objectives

To systematically review the literature on TSAs in LC patients, understand the physiopathology, identify potential preventive and Tx strategies and to further encourage research in this area.

Methods

Literature search on English language articles indexed to PubMed, CINALH, SCOPUS and Web of Science using MeSH terms “Lung neoplasms”,”Dysgeusia”, “Olfaction Disorders”, “Carcinoma, Small Cell”,”Carcinoma, Non- Small-Cell Lung “Adenocarcinoma of Lung”,”Carcinoma, Large Cell”, and non-MeSH terms “Parageusia”, “Altered Taste”, “Smell Disorder”, “Paraosmia”, “Dysosmia”,”Lung Cancer” and “Oat Cell Carcinoma”.

Results

Thirty-four articles were reviewed. TSAs may follow the diagnosis of LC or develop during cancer Tx. The estimated prevalence of self-reported dysgeusia is 35-38% in treatment-naïve LC patients, and 35-69% in those undergoing Tx, based on studies involving LC patients only.

One prospective pilot trial and 1 RCT demonstrated a clinically significant benefit in combining flavor enhancement, smell and taste training and individualized nutritional counselling; a systematic review, 1 RCT and 1 retrospective study favored using intravenous or oral zinc-based solutions (150mg 2-3 times a day) for the prevention and Tx of chemotherapy (CT) and radiotherapy (RT) -induced mucositis and subsequent dysgeusia.

Conclusions

This is the first review on dysgeusia and dysosmia in LC patients to our knowledge. We propose combining taste and smell training, personalized dietary counselling and flavor enhancement with oral zinc-based solutions (150mg, 2-3 times a day) during CT and/or RT in this population, in order to prevent and help ameliorate Tx-induced dysgeusia and mucositis. However due to study heterogeneity, the results should be interpreted with caution. Developing standardized TSA measurement tools and performing prospective randomized controlled trials to evaluate their effect are warranted.

Recent advances on polaprezinc for medical use (Review)

The present study described the chemical and biological properties of zinc complex of L-carnosine (L-CAZ; generic name, polaprezinc; chemical name, catena-(S)-[µ-[N(α)-(3-aminopropionyl) histidinato (2-) N1, N2, O: N(τ)]-zinc], molecular formula, C₉H₁₄N₄O₃Zn; molecular weight, 291.6404; CAS registry number, 107667-60-7). Characterized as a white or yellowish white crystalline powder, this drug is insoluble in glacial acetic acid and almost insoluble in water, methanol, ethanol and ether. It is soluble in dilute hydrochloric acid, dilute nitric acid and sodium hydroxide solution, and its melting point is 260-270˚C. Polaprezinc is an anti-ulcer drug that was jointly studied and developed by Hamari Chemicals Co., Ltd. and Zeria Pharmaceutical Co., Ltd., and was first approved in Japan in 1994. This review article summarizes the research advances of polaprezinc, including the patents, preparations, synthetic routes, pharmacokinetics, pharmacological effects and application in clinical research.

Antioxidative Characteristics of Chicken Breast Meat and Blood after Diet Supplementation with Carnosine, L-histidine, and β-alanine

The objective of the study was to test the effect of diets supplemented with β-alanine, L-histidine, and carnosine on the histidine dipeptide content and the antioxidative status of chicken breast muscles and blood. One-day-old Hubbard Flex male chickens were assigned to five treatments: control diet (C) and control diet supplemented with 0.18% L-histidine (ExpH), 0.3% β-alanine (ExpA), a mix of L-histidine\β-alanine (ExpH+A), and 0.27% carnosine (ExpCar). After 28 days, chicken breast muscles and blood samples were analyzed for the antioxidant enzyme activity (catalase (CAT), glutathione peroxidase (GPx), superoxide dismutase (SOD)), carnosine and anserine content, amino acid profile, and anti-radical activity (ABTS, DPPH, ferric reducing antioxidant power (FRAP)). The results of the study showed that carnosine supplementation effectively increased body weight and breast muscle share in chicken carcasses. Carnosine and L-histidine supplementation with or without β-alanine increased carnosine content in chicken breast muscles up to 20% (p = 0.003), but the boost seems to be too low to affect the potential antioxidant capacity and amino acid content. The β-alanine-enriched diet lowered dipeptide concentration in chicken blood serum (p = 0.002) and activated catalase in chicken breast muscles in relation to the control group (p = 0.003). It can be concluded that histidine or dipeptide supplementation of chicken diets differently affected the total antioxidant potential: in breast muscles, it increased dipeptide content, while in blood cell sediment (rich in erythrocytes), increased SOD and GPx activities were observed.

COVID-19 and Senotherapeutics: Any Role for the Naturally-occurring Dipeptide Carnosine?

It is suggested that the non-toxic dipeptide carnosine (beta-alanyl-L-histidine) should be examined as a potential protective agent against COVID-19 infection and inflammatory consequences especially in the elderly. Carnosine is an effective anti-inflammatory agent which can also inhibit CD26 and ACE2 activity. It is also suggested that nasal administration would direct the peptide directly to the lungs and escape the attention of serum carnosinase.